On May 22, MLB lawyer Pat Houlihan wrote a letter to MLBPA lawyer Jeff Perconte that said, "We agree with the Association that, under the [March] Agreement, players are not required to accept less than their full prorated pay."
Here’s Major League Baseball’s statement.
With that phrase accusing the union of failing to bargain in good faith, it’s practically written to present to an arbitration panel the moment a grievance is filed.